Well it's been a while since my last post: so happy new year, then. ;-)
(I've been very busy! Among other things adding lots of features to the Memia Cloud Services portfolio management toolset which is currently in development *and* doing a load of business planning around the forthcoming SaaS offering - watch this space...)
Meanwhile, I've recently joined the Cloud Computing Interoperability Forum (CCIF) and while browsing through the forum posts I came across one from Kent Langley of nScaled : "Cloud Computing Stack Update". In this post Kent updates his ontology of the Cloud Stack - copied below. This picture gives a nice "ground up" taxonomy view of the Cloud Stack, from "public utilities" (=power companies) upwards.
However, I'm often struck by the subconsious manifestations of the two primary mindsets at work within the "Cloud" space. Generally people seem to either come from an infrastructure background or a software background, but not both. So while this diagram gives plenty of detail describing everything up to and including "operating system" (ie what I would call "Cloud Computing" but not "Cloud Services"), it doesn't place the same emphasis on the variety within the SaaS space. That is, it's an infrastructure-centric view.
Nothing wrong with that, but as someone working in the Cloud space with a primarily *software* hat on, here's an (equally skewed!) ontology which elaborates a more software-centric view of the Cloud - effectively "above the line". Obviously its horses for courses, but in my opinion if we're trying to define the whole Cloud stack from top to bottom then we need to be more granular when describing the common services living within and across the PaaS/SaaS level. (Feedback invited on the contents of the light blue boxes - this is a first cut and I intend to iterate.)